| This thesis has its origins in understanding the chemical mechanisms of gas formation in nuclear waste storage at Hanford, Washington. Research began at Georgia Tech in 1990 to investigate the thermal mechanisms that led to the formation of hydrogen, nitrous oxide, nitrogen, and ammonia from the high level waste. Mechanisms from these studies suggested that NO − was an intermediate generated from the deterioration of HEDTA in Hanford waste. NO−, which is isoelectronic with molecular oxygen, and the tautomeric HNO and NOH, its conjugate bases, have often been postulated as intermediates in reactions in aqueous solution where N 2O appears as a final product.; The existence of HNO and NOH has been substantiated by gas phase spectroscopy and matrix isolation studies. The ground state of NO− is 3Σ in the gas phase while the 1Δ state is 17.2 kcal mol−1 higher in energy. Extensive gas phase calculations suggest that the heats of formation for the ground state singlet HNO and ground state triplet NOH are respectively 26.0 and 51.0 kcal mol−1 (at 298 K). Contrary to the considerable experimental and theoretical work with NO−, HNO, and NOH in the gas phase, relatively little is known about these species in condensed phases.; Here, evidence for the generation of NO− and HNO in the condensed phase was two-fold. From base-induced decomposition reactions with 9,10-nitroso-9,10-dimethylanthracene, the parent 9,10-dimethylanthracene was formed via a retro-Diels-Alder reaction. A solid hyponitrite salt, the dimer of singlet NO−, was also isolated and characterized by infrared and ultraviolet spectroscopy. In oxidation reactions intended to be a suitable source of NOH or/and triplet NO−, the decomposition of the N-oxide intermediate of 9,10-dihydroanthracen-9,10-imine produced anthracene and revealed evidence of HNO instead. Nitrous oxide, the dimerization and dehydration product of HNO, was detected in the headspace of the sealed reaction flask by gas chromatography. |
